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At least 631 records · Page 35Linked to original sources
PubMed1989

Effect of histamine on the T-cell colony formation of PHA-stimulated cells.

The effect of histamine on T-cell colony formation was studied in human peripheral blood mononuclear cells. Histamine inhibited dose-dependently (10(-4)-10(-6) M) the colony formation of PHA-stimulated T-cells. The inhibition was similar in normal controls and rheumatoid arthritis (RA) patients in spite of the fact that in RA the colony formation was significantly lower than in the normal controls. No increase of colony formation was observed at low concentrations (less than 10(-7) M). Impromidine was less effective than histamine, and pyridylethylamine (PEA) was inactive. Cimetidine counteracted the effect of histamine while chlorpheniramine did not. The results show that colony formation may be inhibited through H2-receptors. This action may be of importance in cellular interactions in tissues with high local histamine concentrations.

Colony-Forming Units Assay↗
PubMed1989

Normal and leukemic lymphocyte membrane fluidity and response to stimulation with ConA and PHA.

In our experiment, lymphocyte membrane was labeled by DPH fluorescence probe. The rate of rotation of the probe can be measured from the value of fluorescence polarization (PDPH). With this method useful information could be provided about membrane fluidity of lymphocytes. It was found that the F value (unit of lipid fluidity of membrane) of leukemic lymphocytes was obviously higher than that of normal ones. Furthermore, the F value of cultured leukemic Ts lymphocytes was the highest. In contrast with normal spleen T-lymphocytes or mixed lymphocytes, the response of malignant lymphocytes to the stimulation with ConA or PHA was reflected in the decrease of PDPH value or the increase of F value. Unexpectedly, the F value of T-lymphocytes from "615" mouse not injected with tumour cells was also higher than that of the mixed. The possibility of using the membrane fluidity as a diagnostic criterion was also discussed.

Animals↗
PubMed1991

Anti-CD3- or PHA-induced cytotoxicity in human intraepithelial and lamina propria lymphocytes.

Morphological data in humans and rodents and functional data of intraepithelial lymphocytes of mice support the idea that cytotoxic cells are a significant population of the human mucosa. Previously it was shown that human IEL have no spontaneous cell-mediated cytotoxicity and that human LPL cells have anti-CD3-mediated cytotoxicity. We confirm that most individuals have anti-CD3- or PHA-mediated cytotoxicity of LPL. In IEL we do not find cytotoxic function in short-term assays. There is no difference between patients with colon cancer and inflammatory bowel disease.

Adult↗
PubMed2000

Characterization and cloning of an (R)-specific trans-2,3-enoylacyl-CoA hydratase from Rhodospirillum rubrum and use of this enzyme for PHA production in Escherichia coli.

An (R)-trans-2,3-enoylacyl-CoA hydratase was purified to near-homogeneity from Rhodospirillum rubrum. Protein sequencing of enriched protein fractions allowed the construction of a degenerate oligonucleotide. The gene encoding the (R)-specific hydratase activity was cloned following three rounds of colony hybridization using the oligonucleotide, and overexpression of the gene in E. coli led to the purification of the enzyme to homogeneity. The purified enzyme used crotonyl-CoA, trans-2,3-pentenoyl-CoA, and trans-2,3-hexenoyl-CoA with approximately equal specificity as substrates in the hydration reaction. However, no activity was observed using trans-2,3-octenoyl-CoA as a substrate, but this compound did partially inhibit crotonyl-CoA hydration. Based on the nucleotide sequence, the protein has a monomeric molecular weight of 15.4 kDa and is a homotetramer in its native form as determined by gel filtration chromatography and native PAGE. The hydratase was expressed together with the PHA synthase from Thiocapsa pfennigii in E. coli strain DH5alpha. Growth of these strains on oleic acid resulted in the production of the terpolyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) .

Acyl Coenzyme A↗
PubMed2003

Biosynthesis of medium-chain-length poly(hydroxyalkanoates) with altered composition by mutant hybrid PHA synthases.

Pseudomonas resinovorans harbors two isogenic poly(hydroxyalkanoates) (PHAs) synthase genes ( phaC1(Pre), phaC2(Pre)) responsible for the production of intracellular medium-chain-length (mcl-)PHAs. Sequence analysis showed that the putative gene-products of these genes contain a conserved alpha/beta-hydrolase fold in the carboxy-terminal half of the proteins. Hybrid genes pha7 and pha8 were constructed by exchanging the alpha/beta-hydrolase-fold coding portions of phaC1(Pre) and phaC2(Pre) at the 3' terminal. When grown with decanoate as carbon source, the pha7- or pha8-transformed Escherichia coli LS1298 produced PHAs containing 73-75% beta-hydroxydecanoate (beta-HD) and 25-27% beta-hydroxyoctanoate (beta-HO). Deletion mutants, Delta pha7 and Delta pha8, were isolated during the PCR-based construction of pha7 and pha8, respectively. Cells harboring these mutants produced PHAs containing 55-60 mol% beta-HD and 40-45 mol% beta-HO. These results demonstrate the feasibility of generating active hybrid mcl-PHA synthase genes and their mutants with the potential of producing polymers having a varied repeat-unit composition.

Acyltransferases↗
PubMed2006

Sporadic aneuploidy in PHA-stimulated lymphocytes of Turner's syndrome patients.

In line with the view that aneuploidy destabilizes the karyotype, initiating an autocatalytic process that gives rise to further loss and/or gain of chromosomes, we examined whether a constitutional aneuploidy such as monosomy for one chromosome is associated with sporadic loss and/or gain of other chromosomes. We used PHA-stimulated lymphocytes from eight women with Turner's syndrome (six displayed X chromosome monosomy ranging from 60.2% to 97.9%, and two were below 10%), and eight healthy women who served as a control group. Fluorescence in-situ hybridization (FISH), applied at interphase, was used to evaluate the level of aneuploidy for three randomly selected chromosomes (autosomes 8, 15 and 18) in each sample. For each tested chromosome, our results showed a significantly higher level of aneuploid cells in the samples from patients than in those from controls (p < 0.01). The mean level of aneuploid cells for all three tested autosomes was almost twice as high in the patient samples as in the control samples (p < 0.002). It is noteworthy that, in the Turner's syndrome patients, X chromosome disomic cells also displayed increased levels of aneuploidy. It is possible that monosomy of X chromosome in female cells destabilizes their own genome and also affects X disomic cells in the region. One may also speculate that a common factor(s) is involved with both constitutional and sporadic aneuploidy.

Adolescent↗
PubMed1987

Effect of vanadate of PHA-induced proliferation of human lymphocytes from young and old subjects.

The effect of sodium orthovanadate on mitogen-induced proliferation of lymphocytes from young and old human subjects is reported. We found that vanadate is not mitogenic per se; it has an inhibitory effect during the first 3 days of culture, when both differentiation and proliferation take place; it enhances DNA synthesis, acting as a co-mitogen, in the following days of culture, when proliferation prevails. In spite of the fact that lymphocytes from the two groups differ in their responsiveness to PHA and in the activity of (Na+,K+)ATPase, no difference was found as for the effects of vanadate.

Adolescent↗
PubMed1992

Anchored anti-HLA class I monoclonal antibody fails to induce inhibition of PHA-activated lymphocytes proliferation.

It is known that anti-HLA Class I antibodies inhibit the proliferative response of PHA-activated T-lymphocytes. We found that plastic- or sepharose-linked anti-HLA Class I monoclonal antibody 01.65 does not inhibit either [3H]Thymidine incorporation or recruitment in the cell cycle, nor does it reduce the expression of c-myc mRNA and the membrane expression of Interleukin-2 Receptor and Transferrin Receptor. Furthermore, particulate Protein Kinase C is not affected by anchored anti-HLA Class I monoclonal antibody 01.65. We suggest that anti-HLA Class I monoclonal antibody may act through crosslinking or internalization of HLA Class I antigens.

Antibodies, Monoclonal↗
PubMed1984

Efferent connections of the dorsal tegmental region in the rat, studied by means of anterograde transport of the lectin Phaseolus vulgaris-leucoagglutinin (PHA-L).

Efferent connections of the dorsal tegmental region (DTR) of the rat were studied with anterograde tracing of the lectin Phaseolus vulgaris-leucoagglutinin (PHA-L). The results demonstrate that DTR fibers reach widespread mesencephalic, diencephalic and telencephalic structures which for the most part can be characterized as limbic, i.e. the interpeduncular, mammillary, habenular, anterior and medial thalamic and septal nuclei and limbic cortical areas. In addition, structures such as the prepositus hypoglossi, lateral geniculate and superior colliculus receive input from DTR.

Animals↗
PubMed1985

A method for anterograde axonal tracing of chemically specified circuits in the central nervous system: combined Phaseolus vulgaris-leucoagglutinin (PHA-L) tract tracing and immunohistochemistry.

A method is described for combining anterograde axonal tract tracing using concurrent double immunohistochemical localization of axonally transported Phaseolus vulgaris-leucoagglutinin (PHA-L) and endogenous neural antigens. With this technique, some projections of the substantia nigra and the paraventricular hypothalamic nucleus are examined to demonstrate advantages offered by this approach for tracing chemically specified circuits in the central nervous system.

Animals↗
PubMed1986

The projection from the parataenial thalamic nucleus, as demonstrated by the Phaseolus vulgaris-leucoagglutinin (PHA-L) method, identifies a subterritorial organization of the ventral striatum.

The thalamic projection to the ventral striatum was examined in the rat by immunohistochemistry after iontophoretic injections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into the parataenial thalamic nucleus. A continuous dense terminal field was observed in the nucleus accumbens and the striatal cell bridges, as well as in the adjoining striatal parts of the olfactory tubercle. These observations provide further evidence of the relevance of the ventral striatal concept.

Animals↗
PubMed1991

Efferent projections of the infralimbic (area 25) region of the medial prefrontal cortex in the rat: an anterograde tracer PHA-L study.

The efferent projections of the infralimbic region (IL) of the medial prefrontal cortex of the rat were examined by using the anterograde transport of Phaseolus vulgaris leucoagglutinin (PHA-L). Major targets of the IL were found to include the agranular insular cortex, olfactory tubercle, perirhinal cortex, the whole amygdaloid complex, caudate putamen, accumbens nucleus, bed nucleus of the stria terminalis, midline thalamic nuclei, the lateral preoptic nucleus, paraventricular nucleus, supramammillary nucleus, medial mammillary nucleus, dorsal and posterior areas of the hypothalamus, ventral tegmental area, central gray, interpeduncular nucleus, dorsal raphe, lateral parabrachial nucleus and locus coeruleus. Previously unreported projections of the IL to the anterior olfactory nucleus, piriform cortex, anterior hypothalamic area and lateroanterior hypothalamic nucleus were observed. The density of labeled terminals was especially high in the agranular insular cortex, olfactory tubercle, medial division of the mediodorsal nucleus of the thalamus, dorsal hypothalamic area and the lateral division of the central amygdaloid nucleus. Several physiological and pharmacological studies have suggested that the IL functions as the 'visceral motor' cortex, involved in autonomic integration with behavioral and emotional events. The present investigation is the first comprehensive study of the IL efferent projections to support this concept.

Amygdala↗
PubMed1992

Convergence of subthalamic and striatal efferents at pallidal level in primates: an anterograde double-labeling study with biocytin and PHA-L.

Small injections of two highly sensitive anterograde tracers, Phaseolus vulgaris-leucoagglutinin (PHA-L) and biocytin, into the striatum and the subthalamic nucleus of squirrel monkeys (Saimiri sciureus) have revealed a high degree of convergence of striatal and subthalamic fibers upon single pallidal cells. Both afferent systems formed highly complex band-like patterns that were largely in register with one another. At single cell level, the somata of pallidal neurons were closely surrounded by subthalamic terminal varicosities, whereas the dendrites were entwined mostly by striatal fibers. Typically, a subthalamopallidal fiber coursed in a caudorostral direction and arborized according to a uniform pattern along its trajectory in the pallidum. Numerous thin and markedly varicose axon collaterals detached themselves at right angle from the main subthalamopallidal fiber. These highly branched collaterals were mostly oriented along the mediolateral plane and entwined rather loosely the dendrites but surrounded very closely the somata of pallidal neurons. In contrast, a striatopallidal fiber travelled in a rostrocaudal direction. Its initial segment made only en passant contacts with pallidal cell bodies, whereas its distal end closely entwined the dendrites of pallidal neurons, forming arrangements similar to 'woolly' type fibers. These results suggest that a single subthalamic fiber may influence a rather large collection of pallidal neurons in a similar fashion, compared to the striatal input which appears to exert a more specific control upon selected sets of the same pallidal neurons.

Animals↗
PubMed1992

Spinal and trigeminal lamina I input to the locus coeruleus anterogradely labeled with Phaseolus vulgaris leucoagglutinin (PHA-L) in the cat and the monkey.

Terminal fibers anterogradely labeled with Phaseolus vulgaris leucoagglutinin (PHA-L) were observed in the locus coeruleus in the brainstem of the cat and the cynomolgus monkey following injections in lamina I of the spinal or medullary dorsal horn. Thus, thermoreceptive- or nociceptive-specific lamina I cells that project to the locus coeruleus could directly influence arousal, vigilance, and the descending control of spinal integration.

Animals↗
PubMed1989

Fibrillar center distribution in nucleoli of PHA-stimulated human lymphocytes.

We have utilized acidic toluidine blue staining for RNA and immunofluorescence staining for RNA polymerase 1 to visualize the distribution of fibrillar centers (FCs) in nucleoli of PHA-stimulated human lymphocytes. At 0 h, there is a single large fibrillar center in each nucleolus which splits into smaller and more numerous FCs until the number of FCs reaches five, the number of nucleolus organizers in normal haploid human cells. With time, each FC then "unwinds" to form linear arrays of smaller FCs until the maximum number of FCs approaches the ribosomal gene copy number of 200 at 48 h in culture. It is hypothesized that in the most active state, each nucleolar FC visualized by RNA polymerase 1 staining actually represents a single transcription unit and the distance between adjacent FCs is occupied by the nontranscribed spacer region. We conclude that the number of fibrillar centers per nucleolus can be used as a direct quantitative measure of nucleolar transcriptional activity.

Cell Cycle↗
PubMed1992

Deoxynucleotide pools and DNA synthesis in resting and PHA-stimulated human lymphocytes treated with mutagens.

In resting and PHA-stimulated PBL treated with uv light or MMS we measured the sizes of the dTTP and dATP pools and the variation of ATP content taken as an indicator of cytotoxicity. The effects on DNA synthesis were examined by measuring DNA repair (unscheduled DNA synthesis) in resting PBL and the inhibition of DNA replication in stimulated PBL. While both treatments affected DNA synthesis, only MMS perturbed dNTP pools and decreased the intracellular concentration of ATP. All the effects were more evident in cycling than in resting lymphocytes.

Adenosine Triphosphate↗
PubMed1991

Trajectory of redirected corticospinal axons after unilateral lesion of the sensorimotor cortex in neonatal rat; a phaseolus vulgaris-leucoagglutinin (PHA-L) tracing study.

The corticospinal neurons of the rat project almost exclusively to the contralateral spinal cord. Retrograde and anterograde tracing experiments showed that only about 2-4% of the corticospinal neurons of the sensorimotor cortex project to the ipsilateral spinal cord in the normal rat. The large majority of corticospinal axons (more than 90%) travel at spinal level at the base of the contralateral dorsal funiculus; in addition a few axons run in the contralateral lateral funiculus and at the base of the dorsal horn. The undecussated axons run in the ipsilateral dorsal (about 1-2%) and ventral (about 1-2%) funiculi. The rearrangement of the corticospinal projections was studied with various tracing methods in rats subjected to unilateral lesion of the sensorimotor cortex at Postnatal Day 2 to 4. Spinal injections of the tracer WGA-HRP that were restricted to the side opposite to the cortical lesion showed a significant increase of retrogradely labeled corticospinal neurons in the intact cortex as compared to the proportion of ipsilateral projections in control experiments. This was consistent with an increased density of anterogradely labeled corticospinal terminals in the spinal cord ipsilateral to an injection of WGA-HRP in the motor cortex opposite to neonatal lesion, in comparison to normal rats. The trajectory of these "aberrant" ipsilateral corticospinal projections resulting from the neonatal lesion of the opposite sensorimotor cortex was analyzed by means of the anterograde tracer phaseolus vulgaris-leucoagglutinin (PHA-L), injected in the motor cortex. These data indicated that decussated corticospinal axons recross at spinal levels, close to their terminal zone, where they appear to ramify and terminate in the spinal gray including the motoneurons. Such recrossing axons thus represent one new possible mechanism, among other previously reported ones, contributing to the increase of ipsilateral corticospinal projections in rats subjected to neonatal cortical lesion.

Animals↗
PubMed1976

Enrichment of PHA transformed lymphocytes in samples containing mixed populations.

A dextran density gradient centrifugation method has been used to separate PHA transformed lymphocytes from nontransformed lymphocytes obtained from rat blood. Fifty-four percent of the transformed lymphocytes were recovered in the fraction at a density of 1.0620 g/ml. Eighty-five percent of the cells in this fraction were transformed cells while the remainder were non-transformed lymphocytes.

Animals↗